Deployment of multiple biliary stents

ABSTRACT

Apparatus (20) is provided for use with a guidewire (12). The apparatus includes a guide tube (22) having a guidewire-engaging portion (122) and a slit (28) extending proximally along a wall of the guide tube, from a distal end (32) of the tube, a proximal end (29) of the slit being located distally to a proximal end (30) of the tube. A first stent (52) surrounds the tube and is advanceable together with the tube into a lumen of a subject, the first stent being slidably advanceable off the distal end of the tube; and a second stent (54), proximal to the first stent, surrounding a proximal portion of the tube, and advanceable off the distal end of the tube into the lumen, and placed alongside the first stent subsequently to advancement of the first stent off the distal end of the tube. Other applications are also described.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application is continuation of U.S. application Ser. No.16/064,843 which is a national stage entry of PCT/IL2016/051368, filedDec. 22, 2016 which is incorporated herein by reference in its entirety.PCT/IL2016/051368 claims the priority of U.K. Patent Application No.1522683.0 filed Dec. 22, 2015, which is incorporated herein byreference.

FIELD OF THE INVENTION

Embodiments of the present invention relate generally to medical devicesand more particularly to methods and apparatus for deploying multiplestents in a lumen of a subject.

BACKGROUND

Stents are typically deployed within a lumen of a body of a subject forvarious reasons. In some cases, a stent is deployed within a lumen inorder to widen a narrowed section of the lumen. For example, insertionof a biliary stent into a bile duct is used to treat obstructions andstrictures that occur in the bile duct. There are several conditions,malignant or benign, that can cause strictures of the bile duct.Pancreatic cancer is a common malignant cause of strictures of the bileduct. Noncancerous causes of bile duct stricture may include injury tothe bile duct that occurs during surgery for gallbladder removal, andpancreatitis.

A biliary stent is typically a tube-like structure that is used tosupport a narrowed part of the bile duct and inhibit the reformation ofthe stricture.

SUMMARY OF THE INVENTION

In accordance with some applications of the present invention, apparatusand method are provided for deployment of more than one stent (e.g., twostents) within a lumen of a subject. For example, two or more stents aredeployed within a common bile duct of a subject in order to treatbiliary strictures and obstructions. Typically, the two or more stents,e.g., two, three or four stents, are deployed alongside each otherwithin the common bile duct to facilitate relieving of the biliarystricture. Typically, a guide tube is used to deploy the more than onestents (e.g., a first and a second stent) in the lumen of the subject.The guide tube has a proximal end at a proximal portion thereof, and adistal end at a distal portion thereof. In this context, in thespecification and in the claims, “proximal” means closer to the orificethrough which the guide tube or stent is originally placed into thebody, and “distal” means further from this orifice. The guide tube istypically shaped to define a guidewire-engaging portion, e.g., a hole,through a wall of the guide tube, the hole being located at the distalportion of the guide tube. Additionally, the guide tube is shaped todefine a slit extending proximally along the wall of the guide tube,from the distal end of the guide tube. A proximal end of the slit istypically located distally to the proximal end of the guide tube.Additionally, a proximal end of the slit is typically located proximallyto the hole.

During delivery into the lumen of the subject, the first stent surroundsthe guide tube and is advanced together with the guide tube into thelumen of the subject. Typically, the first stent is slidable along theguide tube such that the proximal end of the first stent is disposeddistally to the proximal end of the slit of the guide tube while thedistal end of the first stent is disposed proximally to the hole of theguide tube. When positioned at a desired site within the lumen of thesubject, the first stent is slidably advanced off of the distal end ofthe guide tube and deployed within the lumen.

The second stent is disposed proximal to the first stent, and surroundsa proximal portion of the guide tube. The second stent is shaped andsized to be advanced over the guide tube and off of the distal end ofthe guide tube into the lumen of the subject. The second stent is placedalongside the first stent subsequently to advancement of the first stentoff of the distal end of the guide tube.

In accordance with some applications of the present invention, the firstand second stents are delivered to the lumen of the subject withoutremoving the guide tube from the body of the subject followingdeployment of the first stent in order to mount the second stent. Asprovided by some applications of the present invention, the first andsecond stents are mounted onto the guide tube and advanced into thesubject's body to be deployed subsequently within the lumen of thesubject, as described above.

There is therefore provided in accordance with some applications of thepresent invention, apparatus for use with a guidewire, the apparatusincluding:

a guide tube shaped to define (a) a guidewire-engaging portion at adistal portion of the guide tube, and (b) a slit extending proximallyalong a wall of the guide tube, from a distal end of the guide tube, aproximal end of the slit being located distally to a proximal end of theguide tube;

a first stent surrounding the guide tube so as to be advanceabletogether with the guide tube into a lumen of a subject, the first stentbeing slidable along the guide tube such that a proximal end of thefirst stent is disposable distally to the proximal end of the slit whilea distal end of the first stent is disposed proximally to theguidewire-engaging portion, the first stent being slidably advanceableoff the distal end of the guide tube; and

a second stent, proximal to the first stent, surrounding a proximalportion of the guide tube, and shaped and sized to be advanceable alongthe guide tube and off the distal end of the guide tube into the lumen,and placed alongside the first stent subsequently to advancement of thefirst stent off the distal end of the guide tube,

the guide tube is shaped such that when the guidewire is disposed (i) atleast in part in a lumen of the guide tube, (ii) passing through adistal-end opening of the guide tube, (iii) passing through theguidewire-engaging portion of the guide tube, and (iv) passing throughthe proximal end of the slit:

-   -   the first stent is (i) constrained from distal motion past the        guidewire-engaging portion, and (ii) constrained from proximal        motion past the proximal end of the slit.

For some applications, the guidewire-engaging portion is shaped as ahole through the wall of the guide tube.

For some applications, the hole is disposed at an angular offset of90-180 degrees from the slit, with respect to a central longitudinalaxis of the guide tube.

For some applications, the hole is disposed at an angular offset of 180degrees from the slit, with respect to the central longitudinal axis ofthe guide tube.

For some applications, a distance between a center of the hole and thedistal end of the guide tube is at least 5 mm.

For some applications, a distance between a center of the hole and thedistal end of the guide tube is less than 200 mm.

For some applications, the hole is shaped to define an elliptical holehaving a major axis oriented in parallel with a longitudinal axis of theguide tube.

For some applications, the guide tube is shaped such that when theguidewire is disposed (i) at least in part in the lumen of the guidetube, (ii) passing through the distal-end opening of the guide tube,(iii) passing through the guidewire-engaging portion of the guide tube,and (iv) passing through the proximal end of the slit:

-   -   the second stent is constrained from distal motion past the        proximal end of the slit.

For some applications, the apparatus further includes the guidewire.

For some applications, the first stent is slidably advanceable off thedistal end of the guide tube when the guidewire is not passing throughthe guidewire-engaging portion of the guide tube.

For some applications, the lumen of the subject includes a common bileduct of the subject, and the apparatus is advanceable into the commonbile duct.

For some applications, the first stent has a length of 5-15 cm.

For some applications, the slit has a length that is greater than thelength of the first stent.

For some applications, the second stent has a length of 5-15 cm.

For some applications, the slit has a length of 5-15 cm.

For some applications, the slit has a length that is: (a) greater than alength of the first stent, and (b) less than a sum of the length of thefirst stent and a length of the second stent.

For some applications, the slit defines two slit edges that are parallelto a central longitudinal axis of the guide tube, a distance between afirst one of the slit edges and a second one of the slit edges being0.45-0.9 mm.

For some applications, the slit defines two slit edges that are parallelto a central longitudinal axis of the guide tube, such that, were theguide tube to be viewed from the distal end of the guide tube, an angleof 10-80 degrees is formed that is defined by:

(a) a first line extending from the central longitudinal axis to a firstone of the slit edges, and

(b) a second line extending from the central longitudinal axis to asecond one of the slit edges.

For some applications, the angle is 20-70 degrees.

For some applications, a distal end of the second stent is disposedproximally to the proximal end of the slit.

For some applications, a distal end of the second stent is disposeddistally to the proximal end of the slit.

For some applications, the first stent includes a self-expandable stent.

For some applications, the second stent includes a self-expandablestent.

For some applications, the apparatus further includes a third stent,proximal to the second stent, surrounding a proximal portion of theguide tube, and shaped and sized to be advanceable along the guide tubeand off of the distal end of the guide tube into the lumen, and placedalongside the first and second stents subsequently to advancement of thefirst and second stents off of the distal end of the guide tube.

For some applications, the apparatus further includes a fourth stent,proximal to the third stent, surrounding a proximal portion of the guidetube, and shaped and sized to be advanceable along the guide tube andoff of the distal end of the guide tube into the lumen, and placedalongside the first, second and third stents subsequently to advancementof the first, second, and third stents off of the distal end of theguide tube.

For some applications, the slit is shaped to define theguidewire-engaging portion and a distance between a first one of theslit edges and a second one of the slit edges at the guidewire-engagingportion is 0.09-0.45 mm.

For some applications, the guidewire-engaging portion has a length of0.45-4.5 mm.

There is further provided in accordance with some applications of thepresent invention apparatus including:

a guide tube shaped to define (a) a hole through a wall of the guidetube at a distal portion of the guide tube, and (b) a slit extendingproximally along the wall of the guide tube, from a distal end of theguide tube, a proximal end of the slit being located distally to aproximal end of the guide tube;

a first stent surrounding the guide tube so as to be advanceabletogether with the guide tube into a lumen of a subject, the first stentbeing slidable along the guide tube such that a proximal end of thefirst stent is disposable distally to the proximal end of the slit whilea distal end of the first stent is disposed proximally to the hole, thefirst stent being slidably advanceable off of the distal end of theguide tube; and

a second stent, proximal to the first stent, surrounding a proximalportion of the guide tube, and shaped and sized to be advanceable alongthe guide tube and off of the distal end of the guide tube into thelumen, and placed alongside the first stent subsequently to advancementof the first stent off of the distal end of the guide tube.

For some applications, the apparatus further includes a guidewireconfigured to (i) enter a lumen of the guide tube from a distal-endopening of the guide tube, (ii) pass out of the lumen of the guide tubethrough the hole of the guide tube, and (iii) pass into the lumen of theguide tube through the proximal end of the slit, and the first stent is(i) constrained from distal motion past the hole when the guidewire isdisposed within the hole, and (ii) constrained from proximal motion pastthe proximal end of the slit when the guidewire is disposed within theslit.

For some applications, the first stent is slidably advanceable off thedistal end of the guide tube when the guidewire is not disposed withinthe hole.

For some applications, the lumen of the subject includes a common bileduct of the subject, and the apparatus is advanceable into the commonbile duct.

For some applications, the hole is disposed at an angular offset of90-180 degrees from the slit, with respect to a central longitudinalaxis of the guide tube.

For some applications, the hole is disposed at an angular offset of 180degrees from the slit, with respect to the central longitudinal axis ofthe guide tube.

For some applications, a distance between a center of the hole and thedistal end of the guide tube is at least 5 mm.

For some applications, a distance between a center of the hole and thedistal end of the guide tube is less than 200 mm.

For some applications, the first stent has a length of 5-15 cm.

For some applications, the slit has a length that is greater than thelength of the first stent.

For some applications, the second stent has a length of 5-15 cm.

For some applications, the slit has a length of 5-15 cm.

For some applications, the slit has a length that is: (a) greater than alength of the first stent, and (b) less than a sum of the length of thefirst stent and a length of the second stent.

For some applications, the hole is shaped to define an elliptical hole.

For some applications, the major axis of the elliptical hole is orientedin parallel with a longitudinal axis of the guide tube.

For some applications, the elliptical hole has a major axis having alength of 5-10 mm and a minor axis having a length of 0.5-1.0 mm.

For some applications, the major axis is 1.5-4 times longer than theminor axis.

For some applications, the slit defines two slit edges that are parallelto a central longitudinal axis of the guide tube, a distance between afirst one of the slit edges and a second one of the slit edges being0.45-0.9 mm.

For some applications, the slit defines two slit edges that are parallelto a central longitudinal axis of the guide tube, such that, were theguide tube to be viewed from the distal end of the guide tube, an angleof 10-80 degrees is formed that is defined by:

(a) a first line extending from the central longitudinal axis to a firstone of the slit edges, and

(b) a second line extending from the central longitudinal axis to asecond one of the slit edges.

For some applications, the angle is 20-70 degrees.

For some applications, a distal end of the second stent is disposedproximally to the proximal end of the slit.

For some applications, a distal end of the second stent is disposeddistally to the proximal end of the slit.

For some applications, the first stent includes a self-expandable stent.

For some applications, the second stent includes a self-expandablestent.

For some applications, the apparatus further includes a third stent,proximal to the second stent, surrounding a proximal portion of theguide tube, and shaped and sized to be advanceable along the guide tubeand off of the distal end of the guide tube into the lumen, and placedalongside the first and second stents subsequently to advancement of thefirst and second stents off of the distal end of the guide tube.

For some applications, the apparatus further includes a fourth stent,proximal to the third stent, surrounding a proximal portion of the guidetube, and shaped and sized to be advanceable along the guide tube andoff of the distal end of the guide tube into the lumen, and placedalongside the first, second and third stents subsequently to advancementof the first, second, and third stents off of the distal end of theguide tube.

There is further provided in accordance with some applications of thepresent invention, apparatus, including:

a guide tube shaped to define (a) a hole through a wall of the guidetube at a distal portion of the guide tube, and (b) a slit extendingproximally along the wall of the guide tube, from a distal end of theguide tube, a proximal end of the slit being located distally to aproximal end of the guide tube;

a first stent surrounding the guide tube, the first stent being slidablealong the guide tube such that a proximal end of the first stent isdisposable distally to the proximal end of the slit while a distal endof the first stent is disposed proximally to the hole, the first stentbeing slidably advanceable off of the distal end of the guide tube; and

a second stent, proximal to the first stent, surrounding the proximalportion of the guide tube, and shaped and sized to be advanceable overthe guide tube.

For some applications, the apparatus further includes a guidewireconfigured to (i) enter a lumen of the guide tube from a distal-endopening of the guide tube, (ii) pass out of the lumen of the guide tubethrough the hole of the guide tube, and (iii) pass into the lumen of theguide tube through the proximal end of the slit, and the first stent is(i) constrained from distal motion past the hole when the guidewire isdisposed within the hole, and (ii) constrained from proximal motion pastthe proximal end of the slit when the guidewire is disposed within theslit.

For some applications, the first stent is slidably advanceable off thedistal end of the guide tube when the guidewire is not disposed withinthe hole.

For some applications, the hole is disposed at an angular offset of90-180 degrees from the slit, with respect to a central longitudinalaxis of the guide tube.

For some applications, the hole is disposed at an angular offset of 180degrees from the slit, with respect to the central longitudinal axis ofthe guide tube.

For some applications, a distance between a center of the hole and thedistal end of the guide tube is at least 5 mm.

For some applications, a distance between a center of the hole and thedistal end of the guide tube is less than 200 mm.

For some applications, the first stent has a length of 5-15 cm.

For some applications, the slit has a length that is greater than thelength of the first stent.

For some applications, the second stent has a length of 5-15 cm.

For some applications, the slit has a length of 5-15 cm.

For some applications, the slit has a length that is: (a) greater than alength of the first stent, and (b) less than a sum of the length of thefirst stent and a length of the second stent.

For some applications, the hole is shaped to define an elliptical hole.

For some applications, the major axis of the elliptical hole is orientedin parallel with a longitudinal axis of the guide tube.

For some applications, the elliptical hole has a major axis having alength of 5-10 mm and a minor axis having a length of 0.5-1.0 mm.

For some applications, the major axis is 1.5-4 times longer than theminor axis.

For some applications, the slit defines two slit edges that are parallelto a central longitudinal axis of the guide tube, a distance between afirst one of the slit edges and a second one of the slit edges being0.45-0.9 mm.

For some applications, the slit defines two slit edges that are parallelto a central longitudinal axis of the guide tube, such that, were theguide tube to be viewed from the distal end of the guide tube, an angleof 10-80 degrees is formed that is defined by:

(a) a first line extending from the central longitudinal axis to a firstone of the slit edges, and

(b) a second line extending from the central longitudinal axis to asecond one of the slit edges.

For some applications, the angle is 20-70 degrees.

For some applications, a distal end of the second stent is disposedproximally to the proximal end of the slit.

For some applications, a distal end of the second stent is disposeddistally to the proximal end of the slit.

For some applications, the first stent includes a self-expandable stent.

For some applications, the second stent includes a self-expandablestent.

There is further provided in accordance with some applications of thepresent invention, a method including:

providing apparatus including:

-   -   a guide tube shaped to define (a) a hole through a wall of the        guide tube at a distal portion of the guide tube, and (b) a slit        extending proximally along the wall of the guide tube, from a        distal end of the guide tube, a proximal end of the slit being        located distally to a proximal end of the guide tube,    -   a first stent surrounding the distal portion of the guide tube,        and    -   a second stent, proximal to the first stent, surrounding a        proximal portion of the guide tube;

threading a guidewire through the guide tube, such that, following thethreading:

(a) the guidewire enters a lumen of the guide tube from a distal-endopening of the guide tube,

(b) the guidewire passes out of the lumen of the guide tube through thehole of the guide tube,

(c) the first stent is constrained from distal motion past the hole ofthe guide tube, due to the guidewire being disposed within the hole,

(d) the guidewire passes into the lumen of the guide tube through theslit, and

(e) the first stent is constrained from proximal motion past theproximal end of the slit, due to the guidewire being disposed within theslit.

For some applications the method further includes:

advancing the apparatus to a desired location in a lumen of a subjectwhile the guidewire is threaded through the guide tube and an outersurface of the first stent is disposed against the guidewire;

subsequently to the advancing of the apparatus, removing the guidewirefrom the hole;

subsequently to the removing, advancing the first stent along the guidetube and off of the distal end of the guide tube into the lumen untilthe first stent is deployed in the desired location in the lumen of thesubject;

subsequently to advancing the first stent off of the distal end of theguide tube, advancing the second stent along the guide tube and over theguidewire in the lumen of the subject; and

subsequently to advancing the first stent, advancing the second stentoff of the distal end of the guide tube, and placing the second stentalongside the first stent.

There is further provided in accordance with some applications of thepresent invention, a method including:

providing apparatus including:

-   -   a guide tube shaped to define (a) a guidewire-engaging portion        at a distal portion of the guide tube, and (b) a slit extending        proximally along a wall of the guide tube, from a distal end of        the guide tube, a proximal end of the slit being located        distally to a proximal end of the guide tube,    -   a first stent surrounding the distal portion of the guide tube,        and    -   a second stent, proximal to the first stent, surrounding a        proximal portion of the guide tube;

threading a guidewire through the guide tube, such that, following thethreading:

(a) the guidewire enters a lumen of the guide tube from a distal-endopening of the guide tube,

(b) the guidewire passes through the guidewire-engaging portion of theguide tube,

(c) the first stent is constrained from distal motion past theguidewire-engaging portion of the guide tube, due to the guidewirepassing through the guidewire-engaging portion,

(d) the guidewire passes into the lumen of the guide tube through theslit, and

(e) the first stent is constrained from proximal motion past theproximal end of the slit, due to the guidewire being disposed within theslit.

For some applications the method further includes:

advancing the apparatus to a desired location in a lumen of a subjectwhile the guidewire is threaded through the guide tube and an outersurface of the first stent is disposed against the guidewire;

subsequently to the advancing of the apparatus, removing the guidewirefrom the guidewire-engaging portion;

subsequently to the removing, advancing the first stent along the guidetube and off of the distal end of the guide tube into the lumen untilthe first stent is deployed in the desired location in the lumen of thesubject;

subsequently to advancing the first stent off of the distal end of theguide tube, advancing the second stent along the guide tube and over theguidewire in the lumen of the subject; and

subsequently to advancing the first stent, advancing the second stentoff of the distal end of the guide tube, and placing the second stentalongside the first stent.

There is further provided in accordance with some applications of thepresent invention, a method including:

providing (i) a first stent and (ii) a second stent proximal to thefirst stent;

advancing the first stent against a guidewire into a lumen of a subject;

deploying the first stent in the lumen of the subject;

while maintaining the guidewire in the lumen of the subject subsequentlyto deployment of the first stent, advancing the second stent over theguidewire into the lumen of the subject; and

deploying the second stent in the lumen alongside the first stent.

There is further provided in accordance with some applications of thepresent invention, apparatus including:

a first stent configured to be advanced into a lumen of a subjectagainst the guidewire; and

a second stent proximal to the first stent, and configured to beadvanced into the lumen of the subject over the guidewire.

For some applications, the apparatus further includes the guidewire.

For some applications, an outer surface of the first stent is disposedagainst the guidewire and the second stent surrounds the guidewire.

For some applications, the apparatus further includes a third stent,proximal to the second stent and configured to be advanced into thelumen of the subject over the guidewire.

For some applications, the apparatus further includes a fourth stent,proximal to the third stent and configured to be advanced into the lumenof the subject over the guidewire.

The present invention will be more fully understood from the followingdetailed description of applications thereof, taken together with thedrawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a guide tube for deployment of afirst and second stent in a lumen of a subject, in accordance with someapplications of the present invention;

FIG. 2 is a schematic illustration of apparatus for delivery anddeployment of a first and second stent in a lumen of a subject, inaccordance with some applications of the present invention;

FIGS. 3A-H are schematic illustrations depicting a general overview of amethod for deploying first and second stents in a lumen of a subject, inaccordance with some applications of the present invention; and

FIG. 4 is a schematic illustration of an additional configuration of theguide tube for deployment of the first and second stents in the lumen ofthe subject, in accordance with some applications of the presentinvention.

DETAILED DESCRIPTION OF EMBODIMENTS

The present detailed description begins with a description of a guidetube 22 which is used to deploy multiple stents in a lumen of thesubject, in accordance with some applications of the present invention.

Reference is made to FIGS. 1 and 2.

FIG. 1 is a schematic illustration of guide tube 22, in accordance withsome applications of the present invention. As shown, guide tube 22 isshape to define a proximal end 30 at a proximal portion 24 of guide tube22, and a distal end 32 at a distal portion 26 of guide tube 22.

Guide tube 22 is additionally shaped to define a guidewire-engagingportion 122, shown as a hole 40 through a wall 36 of guide tube 22 atdistal portion 26 of the guide tube. Guide tube 22 is furtheradditionally shaped to define a slit 28 extending proximally along wall36 of guide tube 22, from distal end 32 of the guide tube. A proximalend 29 of slit 28 is located distally to proximal end 30 of guide tube22. Additionally, proximal end 29 of slit 28 is located proximally tohole 40.

Typically, hole 40 is disposed at an angular offset alpha of 90-180degrees, e.g., 180 degrees, from slit 28, with respect to a centrallongitudinal axis A1 of the guide tube. Alternatively, a smaller anglealpha is used (e.g., an angle alpha of approximately 60 degrees is shownin FIG. 2). As used in the present application, including in the claims,a “central longitudinal axis” of an elongate structure is the set of allcentroids of transverse cross-sectional sections of the structure alongthe structure. Thus the cross-sectional sections are locallyperpendicular to the central longitudinal axis, which runs along thestructure. (If the structure is circular in cross-section, the centroidscorrespond with the centers of the circular cross-sectional sections.)The central longitudinal axis of a curved elongate structure is curved,rather than straight.

Typically, a distance D1 between a center of hole 40 and distal end 32of guide tube 22 is at least 5 mm and/or less than 200 mm e.g., between5 and 200 mm.

For some applications, hole 40 is shaped to define an elliptical holehaving a major axis W1 which is typically oriented in parallel withlongitudinal axis A1 of guide tube 22. The major axis is typically 1.5-4times longer than a minor axis W2 of hole 40. For example, hole 40 hasmajor axis W1 having a length of 5-10 mm and minor axis W2 having alength of 0.5-1.0 mm.

Slit 28 defines two slit edges 27 that are parallel to centrallongitudinal axis A1 of guide tube 22, typically a distance D2 between afirst one of the slit edges and a second one of the slit edges being0.45-0.9 mm. For some applications, when guide tube 22 is viewed fromdistal end 32 of guide tube 22, an angle theta of 10-80 degrees, e.g.,20-70 degrees, is formed that is defined by: (a) a first line extendingfrom the central longitudinal axis to a first one of the slit edges, and(b) a second line extending from the central longitudinal axis to asecond one of the slit edges.

Reference is still made to FIGS. 1 and 2. FIG. 2 is a schematicillustration of apparatus 20 for delivery and deployment of a firststent 52 and a second stent 54 in a lumen of a subject, in accordancewith some applications of the present invention.

For some applications, apparatus 20 comprises guide tube 22 (asdescribed hereinabove with reference to FIG. 1), and first and secondstents 52 and 54 respectively. As shown, first and second stents 52 and54 surround guide tube 22, second stent 54 being disposed proximally tofirst stent 52 and surrounding proximal portion 24 of guide tube 22.First stent 52 is typically disposed over guide tube 22 such that aproximal end 53 of first stent 52 is disposed distally to proximal end29 of slit 28 of guide tube 22 while a distal end 55 of first stent 52is disposed proximally to hole 40.

For some applications, a distal end 59 of second stent 54 is disposedproximally to proximal end 29 of slit 28. For other applications, distalend 59 of second stent 54 is disposed distally to proximal end 29 ofslit 28.

First stent 52 is slidably advanceable off of distal end 32 of guidetube 22. Additionally, second stent 54, is also shaped and sized to beadvanceable over guide tube 22, typically subsequently to advancement offirst stent 52 off of distal end 32 of guide tube 22.

For some applications, first and second stents 52 and 54 each have alength L1 of 5-15 cm, and slit 28 also has a length L2 of 5-15 cm.Typically, slit 28 has a length that is greater than the length of firststent 52. For some applications, slit 28 has a length that is: (a)greater than a length of first stent 52, and (b) less than a sum of thelength of first stent 52 and a length of second stent 54.

Apparatus 20 is typically advanced into a lumen of the subject, andguide tube 22 facilitates placement of first and second stents 52 and 54within the lumen of the subject.

Reference is now made to FIGS. 3A-H, which depict a general overview ofa method for use of apparatus 20 for deploying first and second stents52 and 54 in a lumen of a subject, in accordance with some applicationsof the present invention. Typically, stents 52 and 54 are deployed inthe lumen of the subject, e.g., a common bile duct of the subject, inorder to manage strictures of the lumen. In accordance with someapplications of the present invention, apparatus 20 is configured suchthat first stent 52 is advanced into the lumen of the subject against aguidewire, and second stent 54 is advanced into the lumen over theguidewire (i.e., surrounding the guidewire).

Reference is made to FIG. 3A. In accordance with some applications ofthe present invention, apparatus 20 (comprising guide tube 22 and firstand second stents 52 and 54, as described hereinabove with reference toFIG. 2) is used in combination with a guidewire 12 to deploy stents 52and 54 alongside each other in the lumen. Guidewire 12 is typicallythreaded through guide tube 22 such that following the threading:

(a) guidewire 12 enters a lumen of guide tube 22 from a distal-end 32opening of guide tube 22,

(b) guidewire 12 passes out of the lumen of guide tube 22 through hole40 of guide tube 22,

(c) first stent 52 is constrained from distal motion past hole 40 ofguide tube 22, due to guidewire 12 being disposed within hole 40,

(d) guidewire 12 passes into the lumen of guide tube 22 through proximalend 29 of slit 28, and

(e) first stent 52 is constrained from proximal motion past proximal end29 of slit 28, due to guidewire 12 being disposed within slit 28.

Following threading of guidewire 12 through guide tube 22 as describedhereinabove, apparatus 20 is advanced into a body of the subject, e.g.,into the small intestine, and into lumen 4 of the common bile duct, asshown in FIG. 3A. As shown, first stent 52 is advanced distally overguide tube 22 and against guidewire 12 (i.e., an outer surface of firststent 52 is disposed against guidewire 12). Due to threading ofguidewire 12 as described hereinabove, stent 52 is advanced distally inlumen 4 while it is constrained from distal motion past hole 40 of guidetube 22. Constrained motion of stent 52 (particularly due to guidewire12 being disposed within hole 40) typically allows for stent 52 to beadvanced to a desired deployment site within lumen 4 in a controlledmanner (i.e., inhibiting uncontrolled distal motion of stent 52, thusallowing the physician to safely perform the implantation at the desireddeployment site).

Additionally, due to guidewire 12 being disposed within slit 28, firststent 52 is constrained from proximal motion past proximal end 29 ofslit 28, allowing the physician to advance stent 52 in a controlledmanner.

Reference is now made to FIGS. 3B-H.

When first stent 52 reaches a desired deployment site within lumen 4,guidewire 12 is removed from hole 40 of guide tube 22, by pullingguidewire 12 proximally in the direction indicated by arrow 11, as shownin FIG. 3B. Guidewire 12 is then typically advanced distally in lumen 4as indicated by arrow 13 (FIG. 3C). Guidewire 12 is thus maintainedwithin lumen 4 and is not removed from lumen 4 at this stage. Removal ofguidewire 12 from hole 40 typically releases first stent 52 and allowsfor guide tube 22 to be pulled proximally in the direction indicated byarrow 15 until guide tube 22 is removed from stent 52, and stent 52 canbe deployed in lumen 4 (FIG. 3D). While pulling guide tube 22 proximallyin the direction indicated by arrow 15, guidewire 12 slides through slit28 of guide tube 22 and is consequently centered within a lumen of theguide tube (FIG. 3E). Centering of guidewire 12 in guide tube 22facilitates using guidewire 12 for deployment of second stent 54 withinlumen 4. Positioning of guidewire 12 in guide tube 22 using slit 28allows second stent 54 to be advanced over guidewire 12, whereas firststent 52 was advanced against (but not while around) guidewire 12.

As shown in FIG. 3F, and indicted by arrow 17, second stent 54 isadvanced distally in lumen 4 over guide tube 22 and over guidewire 12(which is the lumen of guide tube 22). As shown in FIG. 3G, second stent54 continues to be distally advanced in lumen 4 (as indicted by arrows19) until a desired deployment site is reached alongside first stent 52(FIGS. 3F-G). Once second stent 54 is deployed alongside first stent 52,guide tube 22 and guidewire 12 are retracted by being pulled in aproximal direction, as indicated by arrow 21 in FIG. 3H.

As described in FIGS. 3A-H, use of apparatus 20 in accordance with someapplications of the present inventions, allows for deployment of secondstent 54 subsequently to deployment of first stent 52, while maintainingguidewire 12 within lumen 4. Additionally, apparatus 20 allows fordeployment of second stent 54 subsequently to deployment of first stent52, without removing apparatus 20 from the body of the subject followingdeployment of first stent 52 in order to mount second stent 54. Notably,first and second stents 52 and 54 are typically disposed at the sametime on guide tube 22 (also as shown in FIG. 2) when advanced into thesubject's body, to be deployed within the lumen using the techniquesdescribed herein. Reference is made to FIGS. 2-3H. It is noted that forsome applications first and second stents 52 and 54 compriseself-expandable stents.

It is additionally noted that stents are described by way ofillustration and not limitation. The scope of the present inventionincludes the use of any other drainage tube or tube-like structureconfigured to relieve stricture of a lumen of a subject.

Reference is now made to FIGS. 3A-4. FIG. 4 is a schematic illustrationof an additional configuration of guide tube 22 for deployment of firstand second stents 52 and 54 in the lumen of the subject, in accordancewith some applications of the present invention. As describedhereinabove with reference to FIGS. 1-3H, guidewire-engaging portion122, embodied as hole 40, is configured to engage guidewire 12 in such away that it inhibits distal motion of first stent 52 pastguidewire-engaging portion 122 of guide tube 22, due to guidewire 12being engaged by portion 122 (e.g., disposed within hole 40).Guidewire-engaging portion 122 is shown in FIGS. 1-3H as hole 40 by wayof illustration and not limitation. It is noted that guidewire-engagingportion 122 may be shaped to define any other configuration suitable forengaging guidewire 12 in such a manner that will grasp or otherwise holdguidewire 12 and thereby inhibit distal motion of first stent 52 pastguidewire-engaging portion 122 when stent 52 is advanced distallyagainst guidewire 12. It is noted that the techniques described hereinwith reference to FIGS. 3A-H apply to guidewire-engaging portion 122 asshown in FIG. 4 as well.

As shown in FIG. 4, for some applications, edges 27 of slit 28 areshaped to define guidewire-engaging portion 122. Typically, distance D2between a first one of the slit edges and a second one of the slit edgesis 0.45-0.9 mm. However, at guidewire-engaging portion 122, a distanceD3 between slit edges 27 is smaller than distance D2, such that, forexample, D2 is 2-5 times larger than D3. Typically, distance D3 betweenslit edges 27 is 0.09 mm-0.45 mm, e.g., greater than 0.15 mm and/or lessthan 0.4 mm. Typically, guidewire-engaging portion 122 shown in FIG. 4has a length that is 5-10 times longer than D3, e.g., 0.45 mm-4.5 mm,e.g., greater than 1 mm and/or less than 3.5 mm. As shown in FIG. 4,guidewire 12 is typically engaged by, and locked into, the narrowed areain slit 28 which defines guidewire-engaging portion 122. Engagingguidewire 12 by guidewire-engaging portion 122 typically allows forfirst stent 52 to be advanced to a desired deployment site within thelumen of the subject in a controlled manner (i.e., inhibitinguncontrolled distal motion of stent 52 when stent 52 is advanceddistally against guidewire 12, thus allowing the physician to safelyperform the implantation at the desired deployment site).

In other words, when guidewire 12 is disposed (i) at least in part in alumen of guide tube 22, (ii) passing through an opening at distal end 32of guide tube 22, (iii) passing through guidewire-engaging portion 122of guide tube 22, and (iv) passing through proximal end 29 of slit 28,first stent 52 is (i) constrained from distal motion pastguidewire-engaging portion 122, and (ii) constrained from proximalmotion past proximal end 29 of the slit 28. Additionally, when guidewire12 is disposed (i) at least in part in a lumen of guide tube 22, (ii)passing through an opening at distal end 32 of guide tube 22, (iii)passing through guidewire-engaging portion 122 of guide tube 22, and(iv) passing through proximal end 29 of slit 28, second stent 54 isconstrained from distal motion past the proximal end of the slit.

Once first stent 52 is in a desired deployment site in the lumen of thesubject, guidewire 12 is released from guidewire-engaging portion 122 bypulling guidewire 12. Removal of guidewire 12 from guidewire-engagingportion 122 typically releases first stent 52 and allows guide tube 22to be pulled proximally in the direction indicated by arrow 15 (as shownin FIG. 3D) until guide tube 22 is removed from stent 52, and stent 52can be deployed in the lumen of the subject.

It is noted that for other applications, guidewire-engaging portion 122may comprise a clip or any other suitable apparatus for engagement ofguidewire 12.

Reference is made to FIGS. 1-4. It is noted that for some applicationsapparatus 20 is configured to deploy more than two stents, e.g., threeor four stents, in the lumen of the subject (configuration not shown).Typically for such applications, guide tube 22 is shaped to define asecond guidewire-engaging portion e.g., a second hole 40, on proximalportion 24 of tube 22.

Reference is still made to FIGS. 1-4. It is noted that apparatus 20 isdescribed with reference to lumen 4 of a common bile duct by way ofillustration and not limitation. The scope of the present inventionincludes use of apparatus 20 in any suitable lumen to deploy multiplestents in the lumen. For example, techniques and apparatus describedherein may be used in a urethra, and/or in a ureter, and/or in apancreatic duct, and/or in an esophagus, and/or in a trachea of thesubject. Additionally or alternatively, techniques and apparatusdescribed herein may be used to deploy two or more prostatic stents.

It will be appreciated by persons skilled in the art that the presentinvention is not limited to what has been particularly shown anddescribed hereinabove. Rather, the scope of the present inventionincludes both combinations and subcombinations of the various featuresdescribed hereinabove, as well as variations and modifications thereofthat are not in the prior art, which would occur to persons skilled inthe art upon reading the foregoing description.

1. Apparatus for use with a guidewire, the apparatus comprising: a guidetube shaped to define (a) a guidewire-engaging portion at a distalportion of the guide tube, and (b) a slit extending proximally along awall of the guide tube, from a distal end of the guide tube, a proximalend of the slit being located distally to a proximal end of the guidetube; a first stent surrounding the guide tube so as to be advanceabletogether with the guide tube into a lumen of a subject, the first stentbeing slidable along the guide tube such that a proximal end of thefirst stent is disposable distally to the proximal end of the slit whilea distal end of the first stent is disposed proximally to theguidewire-engaging portion, the first stent being slidably advanceableoff the distal end of the guide tube; and a second stent, proximal tothe first stent, surrounding a proximal portion of the guide tube, andshaped and sized to be advanceable along the guide tube and off thedistal end of the guide tube into the lumen, and placed alongside thefirst stent subsequently to advancement of the first stent off thedistal end of the guide tube, wherein the guide tube is shaped such thatwhen the guidewire is disposed (i) at least in part in a lumen of theguide tube, (ii) passing through a distal-end opening of the guide tube,(iii) passing through the guidewire-engaging portion of the guide tube,and (iv) passing through the proximal end of the slit: the first stentis (i) constrained from distal motion past the guidewire-engagingportion, and (ii) constrained from proximal motion past the proximal endof the slit.
 2. The apparatus according to claim 1, wherein theguidewire-engaging portion is shaped as a hole through the wall of theguide tube.
 3. The apparatus according to claim 2, wherein the hole isdisposed at an angular offset of 90-180 degrees from the slit, withrespect to a central longitudinal axis of the guide tube.
 4. Theapparatus according to claim 3, wherein the hole is disposed at anangular offset of 180 degrees from the slit, with respect to the centrallongitudinal axis of the guide tube.
 5. The apparatus according to claim2, wherein a distance between a center of the hole and the distal end ofthe guide tube is at least 5 mm.
 6. The apparatus according to claim 2,wherein a distance between a center of the hole and the distal end ofthe guide tube is less than 200 mm.
 7. The apparatus according to claim2, wherein the hole is shaped to define an elliptical hole having amajor axis oriented in parallel with a longitudinal axis of the guidetube.
 8. The apparatus according to any one of claim 1 or 2, wherein theguide tube is shaped such that when the guidewire is disposed (i) atleast in part in the lumen of the guide tube, (ii) passing through thedistal-end opening of the guide tube, (iii) passing through theguidewire-engaging portion of the guide tube, and (iv) passing throughthe proximal end of the slit: the second stent is constrained fromdistal motion past the proximal end of the slit.
 9. The apparatusaccording to any one of claim 1 or 2, further comprising the guidewire.10. The apparatus according to any one of claim 1 or 2, wherein thefirst stent is slidably advanceable off the distal end of the guide tubewhen the guidewire is not passing through the guidewire-engaging portionof the guide tube.
 11. The apparatus according to any one of claim 1 or2, wherein the lumen of the subject includes a common bile duct of thesubject, and wherein the apparatus is advanceable into the common bileduct.
 12. The apparatus according to any one of claim 1 or 2, whereinthe first stent has a length of 5-15 cm.
 13. The apparatus according toany one of claim 1 or 2, wherein the slit has a length that is greaterthan the length of the first stent.
 14. The apparatus according to anyone of claim 1 or 2, wherein the second stent has a length of 5-15 cm.15. The apparatus according to any one of claim 1 or 2, wherein the slithas a length of 5-15 cm.
 16. The apparatus according to any one of claim1 or 2, wherein the slit has a length that is: (a) greater than a lengthof the first stent, and (b) less than a sum of the length of the firststent and a length of the second stent.
 17. The apparatus according toany one of claim 1 or 2, wherein the slit defines two slit edges thatare parallel to a central longitudinal axis of the guide tube, adistance between a first one of the slit edges and a second one of theslit edges being 0.45-0.9 mm.
 18. The apparatus according to any one ofclaim 1 or 2, wherein the slit defines two slit edges that are parallelto a central longitudinal axis of the guide tube, such that, were theguide tube to be viewed from the distal end of the guide tube, an angleof 10-80 degrees is formed that is defined by: (a) a first lineextending from the central longitudinal axis to a first one of the slitedges, and (b) a second line extending from the central longitudinalaxis to a second one of the slit edges.
 19. The apparatus according toclaim 18, wherein the angle is 20-70 degrees.
 20. The apparatusaccording to any one of claim 1 or 2, wherein a distal end of the secondstent is disposed proximally to the proximal end of the slit.
 21. Theapparatus according to any one of claim 1 or 2, wherein a distal end ofthe second stent is disposed distally to the proximal end of the slit.22. The apparatus according to any one of claim 1 or 2, wherein thefirst stent comprises a self-expandable stent.
 23. The apparatusaccording to any one of claim 1 or 2, wherein the second stent comprisesa self-expandable stent.
 24. The apparatus according to any one of claim1 or 2, further comprising a third stent, proximal to the second stent,surrounding a proximal portion of the guide tube, and shaped and sizedto be advanceable along the guide tube and off of the distal end of theguide tube into the lumen, and placed alongside the first and secondstents subsequently to advancement of the first and second stents off ofthe distal end of the guide tube.
 25. The apparatus according to claim24, further comprising a fourth stent, proximal to the third stent,surrounding a proximal portion of the guide tube, and shaped and sizedto be advanceable along the guide tube and off of the distal end of theguide tube into the lumen, and placed alongside the first, second andthird stents subsequently to advancement of the first, second, and thirdstents off of the distal end of the guide tube.
 26. The apparatusaccording to claim 1, wherein the slit is shaped to define theguidewire-engaging portion and wherein a distance between a first one ofthe slit edges and a second one of the slit edges at theguidewire-engaging portion is 0.09-0.45 mm.
 27. The apparatus accordingto claim 1, wherein the guidewire-engaging portion has a length of0.45-4.5 mm.
 28. Apparatus, comprising: a guide tube shaped to define(a) a hole through a wall of the guide tube at a distal portion of theguide tube, and (b) a slit extending proximally along the wall of theguide tube, from a distal end of the guide tube, a proximal end of theslit being located distally to a proximal end of the guide tube; a firststent surrounding the guide tube so as to be advanceable together withthe guide tube into a lumen of a subject, the first stent being slidablealong the guide tube such that a proximal end of the first stent isdisposable distally to the proximal end of the slit while a distal endof the first stent is disposed proximally to the hole, the first stentbeing slidably advanceable off of the distal end of the guide tube; anda second stent, proximal to the first stent, surrounding a proximalportion of the guide tube, and shaped and sized to be advanceable alongthe guide tube and off of the distal end of the guide tube into thelumen, and placed alongside the first stent subsequently to advancementof the first stent off of the distal end of the guide tube.
 29. Theapparatus according to claim 28, further comprising a guidewireconfigured to (i) enter a lumen of the guide tube from a distal-endopening of the guide tube, (ii) pass out of the lumen of the guide tubethrough the hole of the guide tube, and (iii) pass into the lumen of theguide tube through the proximal end of the slit, and wherein the firststent is (i) constrained from distal motion past the hole when theguidewire is disposed within the hole, and (ii) constrained fromproximal motion past the proximal end of the slit when the guidewire isdisposed within the slit.
 30. The apparatus according to claim 29,wherein the first stent is slidably advanceable off the distal end ofthe guide tube when the guidewire is not disposed within the hole. 31.The apparatus according to claim 28, wherein the lumen of the subjectincludes a common bile duct of the subject, and wherein the apparatus isadvanceable into the common bile duct.
 32. The apparatus according toclaim 28, wherein the hole is disposed at an angular offset of 90-180degrees from the slit, with respect to a central longitudinal axis ofthe guide tube.
 33. The apparatus according to claim 32, wherein thehole is disposed at an angular offset of 180 degrees from the slit, withrespect to the central longitudinal axis of the guide tube.
 34. Theapparatus according to claim 28, wherein a distance between a center ofthe hole and the distal end of the guide tube is at least 5 mm.
 35. Theapparatus according to claim 28, wherein a distance between a center ofthe hole and the distal end of the guide tube is less than 200 mm. 36.The apparatus according to any one of claims 28-35, wherein the firststent has a length of 5-15 cm.
 37. The apparatus according to claim 36,wherein the slit has a length that is greater than the length of thefirst stent.
 38. The apparatus according to any one of claims 28-35,wherein the second stent has a length of 5-15 cm.
 39. The apparatusaccording to any one of claims 28-35, wherein the slit has a length of5-15 cm.
 40. The apparatus according to any one of claims 28-35, whereinthe slit has a length that is: (a) greater than a length of the firststent, and (b) less than a sum of the length of the first stent and alength of the second stent.
 41. The apparatus according to any one ofclaims 28-35, wherein the hole is shaped to define an elliptical hole.42. The apparatus according to claim 41, wherein the major axis of theelliptical hole is oriented in parallel with a longitudinal axis of theguide tube.
 43. The apparatus according to claim 41, wherein theelliptical hole has a major axis having a length of 5-10 mm and a minoraxis having a length of 0.5-1.0 mm.
 44. The apparatus according to claim43, wherein the major axis is 1.5-4 times longer than the minor axis.45. The apparatus according to any one of claims 28-35, wherein the slitdefines two slit edges that are parallel to a central longitudinal axisof the guide tube, a distance between a first one of the slit edges anda second one of the slit edges being 0.45-0.9 mm.
 46. The apparatusaccording to any one of claims 28-35, wherein the slit defines two slitedges that are parallel to a central longitudinal axis of the guidetube, such that, were the guide tube to be viewed from the distal end ofthe guide tube, an angle of 10-80 degrees is formed that is defined by:(a) a first line extending from the central longitudinal axis to a firstone of the slit edges, and (b) a second line extending from the centrallongitudinal axis to a second one of the slit edges.
 47. The apparatusaccording to claim 46, wherein the angle is 20-70 degrees.
 48. Theapparatus according to any one of claims 28-35, wherein a distal end ofthe second stent is disposed proximally to the proximal end of the slit.49. The apparatus according to any one of claims 28-35, wherein a distalend of the second stent is disposed distally to the proximal end of theslit.
 50. The apparatus according to any one of claims 28-35, whereinthe first stent comprises a self-expandable stent.
 51. The apparatusaccording to any one of claims 28-35, wherein the second stent comprisesa self-expandable stent.
 52. The apparatus according to any one ofclaims 28-35, further comprising a third stent, proximal to the secondstent, surrounding a proximal portion of the guide tube, and shaped andsized to be advanceable along the guide tube and off of the distal endof the guide tube into the lumen, and placed alongside the first andsecond stents subsequently to advancement of the first and second stentsoff of the distal end of the guide tube.
 53. The apparatus according toclaim 52, further comprising a fourth stent, proximal to the thirdstent, surrounding a proximal portion of the guide tube, and shaped andsized to be advanceable along the guide tube and off of the distal endof the guide tube into the lumen, and placed alongside the first, secondand third stents subsequently to advancement of the first, second, andthird stents off of the distal end of the guide tube.
 54. Apparatus,comprising: a guide tube shaped to define (a) a hole through a wall ofthe guide tube at a distal portion of the guide tube, and (b) a slitextending proximally along the wall of the guide tube, from a distal endof the guide tube, a proximal end of the slit being located distally toa proximal end of the guide tube; a first stent surrounding the guidetube, the first stent being slidable along the guide tube such that aproximal end of the first stent is disposable distally to the proximalend of the slit while a distal end of the first stent is disposedproximally to the hole, the first stent being slidably advanceable offof the distal end of the guide tube; and a second stent, proximal to thefirst stent, surrounding the proximal portion of the guide tube, andshaped and sized to be advanceable over the guide tube.
 55. Theapparatus according to claim 54, further comprising a guidewireconfigured to (i) enter a lumen of the guide tube from a distal-endopening of the guide tube, (ii) pass out of the lumen of the guide tubethrough the hole of the guide tube, and (iii) pass into the lumen of theguide tube through the proximal end of the slit, and wherein the firststent is (i) constrained from distal motion past the hole when theguidewire is disposed within the hole, and (ii) constrained fromproximal motion past the proximal end of the slit when the guidewire isdisposed within the slit.
 56. The apparatus according to claim 55,wherein the first stent is slidably advanceable off the distal end ofthe guide tube when the guidewire is not disposed within the hole. 57.The apparatus according to claim 54, wherein the hole is disposed at anangular offset of 90-180 degrees from the slit, with respect to acentral longitudinal axis of the guide tube.
 58. The apparatus accordingto claim 57, wherein the hole is disposed at an angular offset of 180degrees from the slit, with respect to the central longitudinal axis ofthe guide tube.
 59. The apparatus according to claim 54, wherein adistance between a center of the hole and the distal end of the guidetube is at least 5 mm.
 60. The apparatus according to claim 54, whereina distance between a center of the hole and the distal end of the guidetube is less than 200 mm.
 61. The apparatus according to any one ofclaims 54-60, wherein the first stent has a length of 5-15 cm.
 62. Theapparatus according to claim 61, wherein the slit has a length that isgreater than the length of the first stent.
 63. The apparatus accordingto any one of claims 54-60, wherein the second stent has a length of5-15 cm.
 64. The apparatus according to any one of claims 54-60, whereinthe slit has a length of 5-15 cm.
 65. The apparatus according to any oneof claims 54-60, wherein the slit has a length that is: (a) greater thana length of the first stent, and (b) less than a sum of the length ofthe first stent and a length of the second stent.
 66. The apparatusaccording to any one of claims 54-60, wherein the hole is shaped todefine an elliptical hole.
 67. The apparatus according to claim 66,wherein the major axis of the elliptical hole is oriented in parallelwith a longitudinal axis of the guide tube.
 68. The apparatus accordingto claim 66, wherein the elliptical hole has a major axis having alength of 5-10 mm and a minor axis having a length of 0.5-1.0 mm. 69.The apparatus according to claim 68, wherein the major axis is 1.5-4times longer than the minor axis.
 70. The apparatus according to any oneof claims 54-60, wherein the slit defines two slit edges that areparallel to a central longitudinal axis of the guide tube, a distancebetween a first one of the slit edges and a second one of the slit edgesbeing 0.45-0.9 mm.
 71. The apparatus according to any one of claims54-60, wherein the slit defines two slit edges that are parallel to acentral longitudinal axis of the guide tube, such that, were the guidetube to be viewed from the distal end of the guide tube, an angle of10-80 degrees is formed that is defined by: (a) a first line extendingfrom the central longitudinal axis to a first one of the slit edges, and(b) a second line extending from the central longitudinal axis to asecond one of the slit edges.
 72. The apparatus according to claim 71,wherein the angle is 20-70 degrees.
 73. The apparatus according to anyone of claims 54-60, wherein a distal end of the second stent isdisposed proximally to the proximal end of the slit.
 74. The apparatusaccording to any one of claims 54-60, wherein a distal end of the secondstent is disposed distally to the proximal end of the slit.
 75. Theapparatus according to any one of claims 54-60, wherein the first stentcomprises a self-expandable stent.
 76. The apparatus according to anyone of claims 54-60, wherein the second stent comprises aself-expandable stent.
 77. A method, comprising: providing apparatusincluding: a guide tube shaped to define (a) a hole through a wall ofthe guide tube at a distal portion of the guide tube, and (b) a slitextending proximally along the wall of the guide tube, from a distal endof the guide tube, a proximal end of the slit being located distally toa proximal end of the guide tube, a first stent surrounding the distalportion of the guide tube, and a second stent, proximal to the firststent, surrounding a proximal portion of the guide tube; threading aguidewire through the guide tube, such that, following the threading:(a) the guidewire enters a lumen of the guide tube from a distal-endopening of the guide tube, (b) the guidewire passes out of the lumen ofthe guide tube through the hole of the guide tube, (c) the first stentis constrained from distal motion past the hole of the guide tube, dueto the guidewire being disposed within the hole, (d) the guidewirepasses into the lumen of the guide tube through the slit, and (e) thefirst stent is constrained from proximal motion past the proximal end ofthe slit, due to the guidewire being disposed within the slit.
 78. Themethod according to claim 77, further comprising: advancing theapparatus to a desired location in a lumen of a subject while theguidewire is threaded through the guide tube and an outer surface of thefirst stent is disposed against the guidewire; subsequently to theadvancing of the apparatus, removing the guidewire from the hole;subsequently to the removing, advancing the first stent along the guidetube and off of the distal end of the guide tube into the lumen untilthe first stent is deployed in the desired location in the lumen of thesubject; subsequently to advancing the first stent off of the distal endof the guide tube, advancing the second stent along the guide tube andover the guidewire in the lumen of the subject; and subsequently toadvancing the first stent, advancing the second stent off of the distalend of the guide tube, and placing the second stent alongside the firststent.
 79. A method, comprising: providing apparatus including: a guidetube shaped to define (a) a guidewire-engaging portion at a distalportion of the guide tube, and (b) a slit extending proximally along awall of the guide tube, from a distal end of the guide tube, a proximalend of the slit being located distally to a proximal end of the guidetube, a first stent surrounding the distal portion of the guide tube,and a second stent, proximal to the first stent, surrounding a proximalportion of the guide tube; threading a guidewire through the guide tube,such that, following the threading: (a) the guidewire-enters a lumen ofthe guide tube from a distal-end opening of the guide tube, (b) theguidewire passes through the guidewire-engaging portion of the guidetube, (c) the first stent is constrained from distal motion past theguidewire-engaging portion of the guide tube, due to the guidewirepassing through the guidewire-engaging portion, (d) the guidewire passesinto the lumen of the guide tube through the slit, and (e) the firststent is constrained from proximal motion past the proximal end of theslit, due to the guidewire being disposed within the slit.
 80. Themethod according to claim 79, further comprising: advancing theapparatus to a desired location in a lumen of a subject while theguidewire is threaded through the guide tube and an outer surface of thefirst stent is disposed against the guidewire; subsequently to theadvancing of the apparatus, removing the guidewire from theguidewire-engaging portion; subsequently to the removing, advancing thefirst stent along the guide tube and off of the distal end of the guidetube into the lumen until the first stent is deployed in the desiredlocation in the lumen of the subject; subsequently to advancing thefirst stent off of the distal end of the guide tube, advancing thesecond stent along the guide tube and over the guidewire in the lumen ofthe subject; and subsequently to advancing the first stent, advancingthe second stent off of the distal end of the guide tube, and placingthe second stent alongside the first stent.
 81. A method comprising:providing (i) a first stent and (ii) a second stent proximal to thefirst stent; advancing the first stent against a guidewire into a lumenof a subject; deploying the first stent in the lumen of the subject;while maintaining the guidewire in the lumen of the subject subsequentlyto deployment of the first stent, advancing the second stent over theguidewire into the lumen of the subject; and deploying the second stentin the lumen alongside the first stent.
 82. Apparatus for use with aguidewire, the apparatus comprising: a first stent configured to beadvanced into a lumen of a subject against the guidewire; and a secondstent proximal to the first stent, and configured to be advanced intothe lumen of the subject over the guidewire.
 83. The apparatus accordingto claim 82, further comprising the guidewire.
 84. The apparatusaccording to claim 83, wherein an outer surface of the first stent isdisposed against the guidewire and wherein the second stent surroundsthe guidewire.
 85. The apparatus according to claim 84, furthercomprising a third stent, proximal to the second stent and configured tobe advanced into the lumen of the subject over the guidewire.
 86. Theapparatus according to claim 85, further comprising a fourth stent,proximal to the third stent and configured to be advanced into the lumenof the subject over the guidewire.